Airplane retractible tail wheel or skid mount



AIRPLANE RETRACTIBLE TAIL WHEEL 0R SKID MOUNT Filed 001'... 2, 1940 2 Sheets-Sheet l INVENTOR saw 12 A.EDO

ATT NEYS Aug. 8,1944. E. A. EDDY I AIRPLANE RETRACTIBLE TAIL WHEEL OR SKID MOUNT Filed Oct. 2, 1940 2 Sheets-Sheet 2 INVENTOR 00) ,s'pwf/z BY Ararams Patented Aug. 8, 1944 UNITED STATES PATENT OFFICE AIRPLANE RETRACTIBLEl TAIL WHEEL OR SKID MOUNT Edwyn A. Eddy, Stewart Manor, Long Island, N. Y., assignor to Brewster Aeronautical Corporation, Long Island City, N. Y.

Application October 2, 1940, Serial No. 359,405

3 Claims.

advantages of the invention will appear in the specification herein.

In the drawings:

Fig. 1 is a fragmentary side elevation of a tail wheel mounting device of the invention mounted upon an airplane fuselage and illustrating the essential elements thereof when the gear is in extended and retracted positions;

Fig. 2 is a fragmentary section taken substantially along line 11-11 of Fig. 1; and

Fig. 3 is a fragmentary side elevation, on an enlarged scale, of a detail of Fig. 1, with portions broken away to show the inte ior thereof.

The invention is illustrated in the drawings as mounting a tail wheel I upon an airplane fuselage indicated generally by the numeral l2 '(Fig. 1). The tail wheel supporting structure comprises essentially a wheel axle I 4 engaging at opposite ends with side plates of a fork l6 which is mounted in castering relation below a housing IB by means of a spindle 20 extending from the fork l6. The housing I8 is provided with a forwardly disposed bracket portion 22 into which is seated the lower end 24 of a shock absorbing type telescopic strut device. The upper end of the shock absorbing strut isprovided with a tubular portion 26 into which the lower end 24 thereof is slidably fitted in telescoping relation for the shock absorbing action. The tubular portion 26 is fitted adjacent its lower end with a collar bracket 26 which pivotally engages with a fixed portion 36 of the airplane fuselage through means of a pivot pin 32. Thus, unless otherwise retarded, the shock absorbing strut and wheel unit is freely pivotable relative to the fuselage about the horizontal axis of the pivotpin 32.

A control member in the form of an outer casing member 36 is mounted upon the upper end of the shock strut tube 26 in longitudinally slidable relation thereon and is so formed as to extend beyond the upper end of the tube 26 and terminates in a stud portion 38 extending in line with the longitudinal axis of the shock strut. An apertured plate 40 constituting a stationary portion of the airplane fuselage structure is so arranged that the aperture thereof is in registry with the stud 38 when the gear is in fully extended position. .TheHcasing member 36 is provided adjacent its from the apertured plate 40. the bolt 46 progresses under the impulse of the hydraulic pressure into the lower arcuateiy lower end with a pair of ears 42 extending rear- ,wardly therefrom as integral portions thereof. The ears 42 mount, at their rear ends, a pair of aligned sleeves 44 (Fig. 2) which engage a bolt 4.6 arranged to extend at its opposite ends into reversely curving slots 48 of corresponding guide end plate members 50 which extend as integral portions of an adjacent stationary structure of the airplane fuselage. A hydraulic jack 52 of the hydraulic cylinder-piston type is arranged in .the manner of a diagonal strut relative to the and at the other of its ends by means of a pin 56 to a stationary bracket portion 58 of the airplane fuselage. The bolt 46 is provided with roller sleeves (ill in theregions of contact with the end plates 56,'and the slots 48 in the end plates 58 areformed as illustrated in Fig. 1 to provide a mode of operation ofthe mechanism as will be hereinafter described.

Upon introduction of fluid under pressure into the cylinder of the jack 52 the piston device thereof bears laterally and downwardly upon the bolt 46. Because theupper end portion of the slots 48 are vertically disposed the bolt 46 will be restrained thereby from horizontally directed Thus, the bolt 46 will initially move only down- Wardly, and through means of the ears 52 will carry therewith the casing member 35, causing the latter to move longitudinally of the shock strut in such manner as to Withdraw the stud 38 Subsequent to this,

shaped portions of the slots 48 which extend somewhat horizontally, whereby-the bolt 46 will transmit forwardly directed pressures upon the casing member 36'at a position spaced above the line of horizontal pivoting 'of the shock strut about the pin 32. Consequently, the shock strut "24-26 will now be rotated toward the broken so that the wheel II] will partially extend below the fuselage in order tosafeguard the latter in case of accidental omission on the part of the fuselage.

pilot to operate the gear to extended position prior to effecting a landing of the airplane.

To move the gear from retracted to extended position the fluid pressure within the jack 52 is reversed, and the bolt 46 is thus drawn upwardly toward its original position during which operation it is guided by the slots 48 in such manner as to reverse the previously described pivoting movement of the wheel strut. The last phase of this operation is such as to finally cause the upper end of the stud 38 to move into registry with the apertured plate 6!] and then'to cause the casing 36 to slide upwardly relative to the strut 24-26 so as to positively project'the stud 38 into the aperture and to anchor the stud Within the plate 40.

Thus, the mechanism provides a structure which supports the main wheel strut, when in extended position, at three positions; two of these points of support being through direct connection with stationary portions of the airplane Upon release of the locking stud 38 from the fuselage plate 40 and during rotation of the gear toward or away from retracted position the strut is at all times supported at two positions thereon by means of the fixed pin 32 and the jack 52. It will be understood that any suitable form of abutment means may be provided as an integral portion of the fuselage to bear against an end portion of the wheel strut when the gear is in retracted position so as to firmly brace the latter against forces imposed thereon in connection with landings with the gear retracted. Also, any suitable form of additional locking devices may be provided if desired to lock the gear in retracted and extended positions, if desired.

The gear of the invention is illustrated herein as being applied to a tail wheel of the full castering type, and means are shown as being provided for full control of the tail wheel in such manner that it may be released for castering and locked in straight-forward position whenever the gear is in its retracted condition so as to eliminate swinging of the wheel and fork relative to the remainder of the gear during normal flight of the airplane. To this end a locking pin (Fig. 3) is slidably mounted within a cored portion of the housing [8 and is provided with an end portion adapted to extend into registry with a complementary opening in an adjacent portion of the fork H5. The pin 10 is connected to one end of a pull cable 12 which is enclosed in a flexible casing 13 and connected at its other end to a manual control device conveniently disposed with respect to the pilot. A compression spring 14 is mounted upon the housing I8 so asto resiliently urge the pin 10 toward engagement with the fork l6. Thus, the wheel fork may be arranged for free castering movement, as during taxiing of the airplane, by proper pilot adjustment of the cable 12.

A guide device 15 for the cable 72 may be mounted as illustrated in Fig. 1 upon a fixed portion of the fuselage and at such position that upon retraction of the gear to the broken line position illustrated in Fig. 1 the cable 12 will be relaxed and thus the pin 10 will be released for engagement with the locking aperture of the fork l6. Inasmuch as the center of gravity of the fork l6 and the wheel I0 is disposed below the axis of the spindle when the gear is in retracted position, the wheel and fork will thereby automatically move under the forces of gravity into an attitude corresponding to a straight-forward position of the wheel, whereby the locking aperture of the fork will come into registry with the pin l0 and the latter will automatically engage therewith under the force of the spring 14. Upon subsequent extension of the gear to landing position the cable will automatically return to its prior condition and the pin 10 will thereby be retracted from the fork l6 against the action of the spring I4, thus leaving the wheel l0 free to caster.

Thus, it will be understood that the invention provides a rugged and simplified retractible gear which is adapted to support a landing wheel or skid or similar device relative to the fuselage in an improved manner throughout the various phases of the gear movement. It will also be understood that the hydraulic jack device 52 illustrated and described hereinabove may be of any suitable type such as is now presently available to airplane manufacturers, and that the pressure supply means and control means therefor may be of any suitable type. Also, that in lieu of the use of the hydraulic jack 52 illustrated and described hereinabove, the required motion may be imparted to the actuating elements of the gear by any other suitable motor device, and that although only one form of the invention has been shown and described in detail, it will be apparent to those skilled in the art that the invention is not so limited but that various changes may be made therein without departing from the spirit of the invention or the scope of the appended claims.

What is claimed is:

1. A retractable tail support mounting for an aircraft comprising a main strut member pivotally mounted by means of a, connection device intermediately of its ends to a fixed portion of the aircraft, a tubular control member slidably mounted in telescopic relation upon an end portion of said main strut and having a portion adapted to engage a second connection device at another fixed portion of said aircraft to provide a cantilever mounting of said strut upon said aircraft when said main strut is in extended position, an extensible-contractable strut device mounted at one of its ends upon said aircraft fixed structure and directly connected at its other end to said control member at a position between said connection devices and so disposed as to extend substantially, laterally of the direction of said cantilever mounting connection devices and in a direction substantially offset from said first connection device to function as a diagonal brace for said main strut, and a guide device mounted upon a stationary portion of said aircraft and engaging said control member so as to guide the movements of the latter in response to forces of said extensible-contractable strut in such manner as to initially cause said control member to slide within predetermined limits relative to said main strut for disengagement of said control member from said second connection device and .to subsequently direct said extensible-contractable strut forces to motivate said main strut pivotally about said first mentioned connection device into a position of retraction within said aircraft. f

2. A retractable tail support mounting for an aircraft comprising a main strut :member pivotally mounted by means of a connection device intermediately of its ends to a fixed portion of the aircraft, a control member slidably mounted upon an end portion of said main strut and having a portion adapted to engage a second connection device at another fixed portion ofsaid; aircraft to provide a cantilever mounting of said strut upon said aircraft when said main strut is in extended position, a motor device mounted upon said aircraft fixed structure and directly connected to said control member at a position spaced from said first connection device and in- V termediate of said connection devices and so arranged as to impose forces upon said control member in directions laterally of the direction of said cantilever mounting connection devices and at a position substantially offset from said first connection device,,and a guide device mounted upon a stationary portion of said aircraft and engaging said control member so as to guide the movements of the latter in response to forces of said motor device in such manner as to initially cause said control member to slide within predetermined limits relative to said main strut for disengagement of said control member from said second connection device and to subsequently direct said motor device forces to motivate said main strut pivotally about said first mentioned connection device into a position of retraction within said aircraft, a pivot shaft carried by said main strut, a landing wheel mounted upon said pivot shaft so as to provide a castering mounting for said wheel, said main strut and said pivot shaft and said wheel being so relatively arranged that the axis of said pivot shaft is disposed above the center of mass of the castering structure when said strut is in its retracted position.

3. A retractable tail support mounting for an aircraft comprising a main strut member pivotally mounted by means of a connection device intermediately of its ends to a fixed portion of the aircraft, a control member slidably mounted upon an end portion of said main strut and having a portion adapted to engage a second connection device at another fixed portion of said craft and engaging said control member so as to guide the movements of the latter in response to forces of said motor device in such manner as to initially cause said control member to slide within predetermined limits relative to said main strut for disengagement of said control member from said second connection device and to subsequently direct said motor device forces to motivate said main strut pivotally about said first mentioned connection device into a position of retraction within said aircraft, a pivot shaft carried by said main strut, a landing wheel mounted upon said pivot shaft so as to provide a castering mounting for said wheel, said main strut and said pivot shaft and said wheel being so relatively arranged that the axis of said pivot shaft is disposed above the center of mass of the eastering structure when said strut is in its retracted position, and lock means adapted to automatically mov to interlock said main strut and said castering structure when said wheel is disposed in straight forward attitude and only when said strut is in retracted position, and manual control means operably associated with said lock means whereby said lock means may also be manually controllable at will.

EDWYN A. EDDY. 

